Photosynthesis

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Photosynthesis

How do plants get energy?

Photosynthesis – process plants use to trap sun’s energy and build carbohydrates (glucose) that store energy.

Formula: 6CO 2 + 6H 2 O + energy → C 6 H 12 O 6 + 6O 2 6 carbon dioxide + 6 water + energy→ 1 glucose + 6 oxygen

2 Phases of Photosynthesis

1.

2.

2 Phases of Photosynthesis: 1. Light-dependent Reactions – Takes place in chloroplasts – Chloroplast contains pigment called chlorophyll which is green because it reflects green light. (In fall, trees absorb chlorophyll and other colors show through.) light energy (from Sun) → chemical energy (ATP)

2 Phases of Photosynthesis: 2. Light-independent Reactions or Calvin Cycle or Dark Reactions – Does not require light – Uses ATP (from light reactions) to convert CO 2 glucose to

How do plants regulate water & gas exchange?

Guard cells on the underside of leaves open to let in CO 2 and O 2 (waste product) and some H 2 O out (plant “sweating”). The cells are closed when they become flaccid & lose water. The cells open when they are full of water & swollen. This process is called transpiration.

Guard Cells

Guard Cells

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